# coding=utf-8
import ee
from . import utils
import json
import csv
from .. import tools


def fromShapefile(filename, start=None, end=None):
    """ Convert an ESRI file (.shp and .dbf must be present) to a
    ee.FeatureCollection

    At the moment only works for shapes with less than 1000 records and doesn't
    handle complex shapes.

    :param filename: the name of the filename. If the shape is not in the
        same path than the script, specify a path instead.
    :type filename: str
    :param start:
    :return: the FeatureCollection
    :rtype: ee.FeatureCollection
    """
    import shapefile

    wgs84 = ee.Projection('EPSG:4326')
    # read the filename
    reader = shapefile.Reader(filename)
    fields = reader.fields[1:]
    field_names = [field[0] for field in fields]
    field_types = [field[1] for field in fields]
    types = dict(zip(field_names, field_types))
    features = []

    projection = utils.getProjection(filename)

    # filter records with start and end
    start = start if start else 0
    if not end:
        records = reader.shapeRecords()
        end = len(records)
    else:
        end = end + 1

    if (end-start)>1000:
        msg = "Can't process more than 1000 records at a time. Found {}"
        raise ValueError(msg.format(end-start))

    for i in range(start, end):
        # atr = dict(zip(field_names, sr.record))
        sr = reader.shapeRecord(i)
        atr = {}
        for fld, rec in zip(field_names, sr.record):
            fld_type = types[fld]
            if fld_type == 'D':
                value = ee.Date(rec.isoformat()).millis().getInfo()
            elif fld_type in ['C', 'N', 'F']:
                value = rec
            else:
                continue
            atr[fld] = value
        geom = sr.shape.__geo_interface__
        if projection is not None:
            geometry = ee.Geometry(geom, 'EPSG:' + projection) \
                .transform(wgs84, 1)
        else:
            geometry = ee.Geometry(geom)
        feat = ee.Feature(geometry, atr)
        features.append(feat)

    return ee.FeatureCollection(features)


def fromGeoJSON(filename=None, data=None, crs=None):
    """ Create a list of Features from a GeoJSON file. Return a python tuple
    with ee.Feature inside. This is due to failing when attempting to create a
    FeatureCollection (Broken Pipe ERROR) out of the list. You can try creating
    it yourself casting the result of this function to a ee.List or using it
    directly as a FeatureCollection argument.

    :param filename: the name of the file to load
    :type filename: str
    :param crs: a coordinate reference system in EPSG format. If not specified
        it will try to get it from the geoJSON, and if not there it will rise
        an error
    :type: crs: str
    :return: a tuple of features.
    """
    if filename:
        with open(filename, 'r') as geoj:
            content = geoj.read()
            geodict = json.loads(content)
    else:
        geodict = data

    features = []
    # Get crs from GeoJSON
    if not crs:
        filecrs = geodict.get('crs')
        if filecrs:
            name = filecrs.get('properties').get('name')
            splitcrs = name.split(':')
            cleancrs = [part for part in splitcrs if part]
            try:
                if cleancrs[-1] == 'CRS84':
                    crs = 'EPSG:4326'
                elif cleancrs[-2] == 'EPSG':
                    crs = '{}:{}'.format(cleancrs[-2], cleancrs[-1])
                else:
                    raise ValueError('{} not recognized'.format(name))
            except IndexError:
                raise ValueError('{} not recognized'.format(name))
        else:
            crs = 'EPSG:4326'

    for n, feat in enumerate(geodict.get('features')):
        properties = feat.get('properties')
        geom = feat.get('geometry')
        ty = geom.get('type')
        coords = geom.get('coordinates')
        if ty == 'GeometryCollection':
            ee_geom = utils.GEOMETRY_TYPES.get(ty)(geom, opt_proj=crs)
        else:
            ee_geom = utils.GEOMETRY_TYPES.get(ty)(coords, proj=ee.Projection(crs))
        ee_feat = ee.feature.Feature(ee_geom, properties)
        features.append(ee_feat)

    return tuple(features)


def fromKML(filename=None, data=None, crs=None, encoding=None):
    """ Create a list of Features from a KML file. Return a python tuple
    with ee.Feature inside. This is due to failing when attempting to create a
    FeatureCollection (Broken Pipe ERROR) out of the list. You can try creating
    it yourself casting the result of this function to a ee.List or using it
    directly as a FeatureCollection argument.

    :param filename: the name of the file to load
    :type filename: str
    :param crs: a coordinate reference system in EPSG format. If not specified
        it will try to get it from the geoJSON, and if not there it will rise
        an error
    :type: crs: str
    :return: a tuple of features.
    """
    geojsondict = utils.kmlToGeoJsonDict(filename, data, encoding)
    features = geojsondict['features']

    for feat in features:
        # remove styleUrl
        prop = feat['properties']
        if 'styleUrl' in prop:
            prop.pop('styleUrl')

        # remove Z value if needed
        geom = feat['geometry']
        ty = geom['type']
        if ty == 'GeometryCollection':
            geometries = geom['geometries']
            for g in geometries:
                c = g['coordinates']
                utils.removeZ(c)
        else:
            coords = geom['coordinates']
            utils.removeZ(coords)

    return fromGeoJSON(data=geojsondict, crs=crs)


def toDict(collection, split_at=4000):
    """ Get the FeatureCollection as a dict object """
    size = collection.size()
    condition = size.gte(4999)

    def greater():
        size = collection.size()
        seq = tools.ee_list.sequence(0, size, split_at)
        limits = ee.List.zip(seq.slice(1), seq)

        def over_limits(n):
            n = ee.List(n)
            ini = ee.Number(n.get(0))
            end = ee.Number(n.get(1))
            return ee.FeatureCollection(collection.toList(ini, end))

        return limits.map(over_limits)

    collections = ee.List(
        ee.Algorithms.If(condition,
                         greater(),
                         ee.List([collection])))

    collections_size = collections.size().getInfo()

    col = ee.FeatureCollection(collections.get(0))
    content = col.getInfo()
    feats = content['features']

    for i in range(0, collections_size):
        c = ee.FeatureCollection(collections.get(i))
        content_c = c.getInfo()
        feats_c = content_c['features']
        feats = feats + feats_c

    content['features'] = feats

    return content


def toGeoJSON(collection, name, path=None, split_at=4000):
    """ Export a FeatureCollection to a GeoJSON file

    :param collection: The collection to export
    :type collection: ee.FeatureCollection
    :param name: name of the resulting file
    :type name: str
    :param path: The path where to save the file. If None, will be saved
        in the current folder
    :type path: str
    :param split_at: limit to avoid an EE Exception
    :type split_at: int
    :return: A GeoJSON (.geojson) file.
    :rtype: file
    """
    import json
    import os

    if not path:
        path = os.getcwd()

    # name
    if name[-8:-1] != '.geojson':
        fname = name+'.geojson'

    content = toDict(collection, split_at)

    with open(os.path.join(path, fname), 'w') as thefile:
        thefile.write(json.dumps(content))

    return thefile


def toCSV(collection, filename, split_at=4000):
    """ Alternative to download a FeatureCollection as a CSV """
    d = toDict(collection, split_at)

    fields = list(d['columns'].keys())
    fields.append('geometry')

    features = d['features']

    ext = filename[-4:]
    if ext != '.csv':
        filename += '.csv'

    with open(filename, 'w') as thecsv:
        writer = csv.DictWriter(thecsv, fields)

        writer.writeheader()
        # write rows
        for feature in features:
            properties = feature['properties']
            fid = feature['id']
            geom = feature['geometry']['type']

            # match fields
            properties['system:index'] = fid
            properties['geometry'] = geom

            # write row
            writer.writerow(properties)

        return thecsv


def toLocal(collection, filename, filetype=None, selectors=None, path=None):
    """ Download a FeatureCollection to a local file a CSV or geoJSON file.
    This uses a different method than `toGeoJSON` and `toCSV`

    :param filetype: The filetype of download, either CSV or JSON.
        Defaults to CSV.
    :param selectors: The selectors that should be used to determine which
        attributes will be downloaded.
    :param filename: The name of the file to be downloaded
    """
    if not filetype:
        filetype = 'CSV'

    url = collection.getDownloadURL(filetype, selectors, filename)
    thefile = utils.downloadFile(url, filename, filetype, path)
    return thefile


def toAsset(table, assetPath, name=None, create=True, verbose=False, **kwargs):
    """ This function can create folders and ImageCollections on the fly.
    The rest is the same to Export.image.toAsset. You can pass the same
    params as the original function

    :param table: the feature collection to upload
    :type table: ee.FeatureCollection
    :param assetPath: path to upload the image (only PATH, without
        filename)
    :type assetPath: str
    :param name: filename for the image (AssetID will be assetPath + name)
    :type name: str
    :return: the tasks
    :rtype: ee.batch.Task
    """

    # Check if the user is specified in the asset path
    is_user = (assetPath.split('/')[0] == 'users')
    if not is_user:
        user = ee.batch.data.getAssetRoots()[0]['id']
        assetPath = "{}/{}".format(user, assetPath)

    if create:
        # Recrusive create path
        path2create = assetPath #  '/'.join(assetPath.split('/')[:-1])
        utils.createAssets([path2create], 'Folder', True)

    # Asset ID (Path + name)
    assetId = '/'.join([assetPath, name])
    # Description
    description = utils.matchDescription(name)
    # Init task
    task = ee.batch.Export.table.toAsset(table, assetId=assetId,
                                         description=description, **kwargs)
    task.start()
    if verbose:
        print('Exporting {} to {}'.format(name, assetPath))

    return task